Low Air flow from Registers

[desertsled]

Can any one tell me why my fan switch blows like its on half speed when its on high? I just re did the A/c and while it blows cold, I have little volume. I put in a new fan motor, and switch relay and cleaned the intake in the cowl, and reached as far as i could reach in there to clean it out, but still nothing. I can hear the fan blowing very strong but not much coming out the registers. Max and norm are working properly. as well as heat and defrost. I even tried to blow it out with air pressure from the evaporator ,but thats the wrong way of flow. any sugestions????
My theory is the evaporator is full of junk.